Magnetic or electrostatic pivoting of a mobile timepiece element

Abstract

A timepiece sub-assembly including a mobile timepiece element including first and second annular and opposite peripheral surfaces of revolution about a same pivot axis, and a device for guiding pivoting about a theoretical axis of a timepiece mechanism. The first surface is magnetically or electrically charged, and the device includes at least three first surfaces regularly arranged around the theoretical axis, oppositely magnetically or respectively electrically charged to the first surface to repulse it at a first interface. In a watch, the second surface is magnetically or electrically charged, and the device includes at least three second surfaces regularly arranged around the theoretical axis, oppositely magnetically or electrically charged to the second surface to repulse it at a second interface.

The invention claimed is: 
     
       1. A timepiece sub-assembly comprising:
 a mobile timepiece element including at least a first annular peripheral surface of revolution about a pivot axis of the mobile element; and 
 a device for guiding pivoting about a theoretical axis of a timepiece mechanism; 
 wherein the first peripheral surface is electrically charged; and 
 the device further comprising a plurality of carrier structures positioned around a perimeter of the mobile timepiece element, each of the carrier structures including first electrically charged surfaces, positioned opposite to and above the first peripheral surface, to repulse the first peripheral surface at a first interface, to maintain the mobile element in axial levitation in a direction of the theoretical axis, the first electrically charged surfaces including a first upper pole shoe positioned radially closer to the theoretical axis than the first peripheral surface, a second upper pole shoe positioned a same distance from the theoretical axis as the first peripheral surface, and a third upper pole shoe positioned further from the theoretical axis than the first peripheral surface, and a magnetic field emitted at the second upper pole shoe being lower than a magnetic field emitted at the first upper pole shoe and lower than a magnetic field emitted at the third upper pole shoe. 
 
     
     
       2. The timepiece sub-assembly according to  claim 1 , wherein the first electrically charged surfaces of the plurality of carrier structures are regularly arranged around the theoretical axis in a perpendicular plane to the theoretical axis. 
     
     
       3. The timepiece sub-assembly according to  claim 2 , wherein the first electrically charged surfaces of each of the plurality of carrier structures are identical. 
     
     
       4. The timepiece sub-assembly according to  claim 1 , wherein the mobile timepiece element further includes a second annular peripheral surface of revolution about the pivot axis of the mobile element, and planar and parallel to the first annular peripheral surface of revolutions and opposite to each other on either side of the mobile element, and wherein the second peripheral surface is electrically charged, and
 wherein the device further comprises second electrically charged surfaces in each of the plurality of carrier structures and positioned opposite to and below the second peripheral surface to repulse the second peripheral surface, at a second interface, to maintain the mobile element in axial levitation in the direction of the theoretical axis, the second electrically charged surfaces including a first lower pole shoe positioned radially closer to the theoretical axis than the second peripheral surface, a second lower pole shoe positioned a same distance from the theoretical axis as the second peripheral surface, and a third lower pole shoe positioned further from the theoretical axis than the second peripheral surface, and a magnetic field emitted at the second lower pole shoe being lower than a magnetic field emitted at the first lower pole shoe and lower than a magnetic field emitted at the third lower pole shoe. 
 
     
     
       5. The timepiece sub-assembly according to  claim 4 , wherein the second electrically charged surfaces of the plurality of carrier structures are regularly arranged around the theoretical axis in a plane perpendicular to the theoretical axis. 
     
     
       6. The timepiece sub-assembly according to  claim 4 , wherein the first electrically charged surfaces are grouped together on a first ring along the theoretical axis, and/or wherein the second electrically charged surfaces are grouped together on a second ring along the theoretical axis. 
     
     
       7. The timepiece sub-assembly according to  claim 4 , wherein the first peripheral surface is separated from the second peripheral surface by a low dielectric, with a dielectric constant of between 1 and 50 and a dielectric rigidity of more than 10 MV/m, in a median groove comprised in the mobile element. 
     
     
       8. The timepiece sub-assembly according to  claim 4 , wherein the first peripheral surface is adjacent to the second peripheral surface, and wherein the surfaces are electrically charged with opposite polarity. 
     
     
       9. The timepiece sub-assembly according to  claim 4 , wherein, at the first interface, magnetic or electrostatic field lines generated between the first peripheral surface and the first electrically charged ring or the first electrically charged surfaces are tangential to a cylinder centered on the theoretical axis and obliquely incident at the same angle with respect to a direction parallel to the theoretical axis, and wherein, at the second interface, the magnetic or electrostatic field lines are tangential to a cylinder centered on the theoretical axis and obliquely incident at the same angle with respect to a direction parallel to the theoretical axis. 
     
     
       10. A watch comprising at least one timepiece sub-assembly according to  claim 4 , and magnetic and/or electrostatic field insulating or shielding means around the mobile element and the pivoting guide device. 
     
     
       11. A clock comprising at least one timepiece sub-assembly according to  claim 4 , and magnetic and/or electrostatic field insulating or shielding means around the mobile element and the pivoting guide device. 
     
     
       12. The timepiece sub-assembly according to  claim 1 , wherein the mobile element includes a third electrically charged peripheral edge surface, and wherein the device further comprises at least three third surfaces, all positioned opposite to the third peripheral edge surface to ensure centering of the mobile element, and regularly arranged around the theoretical axis. 
     
     
       13. The timepiece sub-assembly according to  claim 1 , wherein the surfaces that are electrically charged are made with electrets. 
     
     
       14. The timepiece sub-assembly according to  claim 1 , wherein the mobile element has no axial pivots. 
     
     
       15. The timepiece sub-assembly according to  claim 1 , wherein the mobile element is a wheel. 
     
     
       16. A timepiece movement comprising at least one timepiece sub-assembly according to  claim 1 , wherein the movement includes magnetic and/or electrostatic field insulating or shielding means around the mobile element and the pivoting guide device. 
     
     
       17. A timepiece sub-assembly comprising:
 a mobile timepiece element including at least a first annular peripheral surface of revolution about a pivot axis of the mobile element; and 
 a device for guiding pivoting about a theoretical axis of a timepiece mechanism; 
 wherein the first peripheral surface is planar and magnetically or electrically charged; and 
 the device further comprising either a first magnetically or respectively electrically charged ring, or at least three first magnetically or respectively electrically charged surfaces, parallel to each other, positioned opposite to and above the first peripheral surface to repulse the first peripheral surface at a first interface, to maintain the mobile element in axial levitation in a direction of the theoretical axis, 
 wherein the one mobile timepiece element includes the second annular peripheral surfaces of revolution about the pivot axis of the mobile element which is parallel to and opposite to the first annular peripheral surface of revolution on either side of the mobile element, 
 wherein the second peripheral surface is magnetically or electrically charged, and 
 wherein the device further comprises either a second magnetically or respectively electrically charged ring, or at least three second magnetically or respectively electrically charged surfaces, parallel to each other, positioned opposite to and below the second peripheral surface to repulse the second peripheral surface, at a second interface, to maintain the mobile element in axial levitation in the direction of the theoretical axis, wherein the first peripheral surface and the second peripheral surface are tilted with respect to pivot axis such that an axis of the first peripheral surface and the second peripheral intersects the pivot axis at a cone angle to form a cone. 
 
     
     
       18. The timepiece sub-assembly according to  claim 17 , wherein each of the first electrically charged surfaces and each of the second electrically charged surfaces has a normal in a plane passing through the theoretical axis and tilted with respect to the pivot axis at a same cone angle, in a same direction as the first peripheral surface and respectively the second peripheral surface, to ensure substantially constant interface widths. 
     
     
       19. The timepiece sub-assembly according to  claim 17 , wherein the first peripheral surface is part of tilted upper pole shoes, and wherein the second peripheral surface is part of tilted lower pole shoes, and are conical and have a same direction of cone aperture that is tilted with respect to the pivot axis at the cone angle, and
 wherein, in combination, each of the first electrically charged surfaces and each of the second electrically charged surfaces has a normal in a plane passing through the theoretical axis and tilted with respect to the pivot axis at the same cone angle, in a same direction as the first peripheral surface and respectively the second peripheral surface, to ensure substantially constant interface widths. 
 
     
     
       20. The timepiece sub-assembly according to  claim 17 , wherein the first peripheral surface is electrically charged, and wherein the device further comprises, either the first electrically charged ring, or at least three of the first electrically charged surfaces, and wherein the second peripheral surface is electrically charged, and wherein the device further comprises, either the second electrically charged ring, or at least three the second electrically charged surfaces. 
     
     
       21. The timepiece sub-assembly according to  claim 17 , wherein the surfaces that are magnetically charged have a remanent field of more than 0.8 Tesla. 
     
     
       22. The timepiece sub-assembly according to  claim 17 , wherein the mobile element is subjected, at the first peripheral surface, to a magnetic field which is generated by at least one electromagnet. 
     
     
       23. The timepiece sub-assembly according to  claim 17 , wherein the first peripheral surface and the second peripheral surface are tilted by 30° with respect to the pivot axis.